It is well known to produce polyethylene by polymerization under high pressures within stirred autoclave-type reactors. Apparatus of this type has been described in the patent literature over the past 30 years or more, for example, as early as Krase et al U.S. Pat. No. 2,396,791 granted to du Pont on Mar. 19, 1946, and, more recently, in Pugh et al U.S. Pat. No. 3,756,996, granted to National Distillers & Chemical Corporation on Sept. 4, 1973.
Stirred autoclaves of the type referred to in the aforesaid Pugh et al patent, for example, have been designed with successively larger reactor volumes as greater production capacities have become desirable. Typically, reactors of this type having lengths of up to about 20 feet, L/D (Length/diameter) ratios of the order of 15 or more, and reaction volumes of up to about 30 cubic feet, have been utilized in the production of low density polyethylene resins. The use of such large volume reactors has, however, posed numerous problems, particularly with respect to increased investment costs, the difficulty and cost of maintenance, susceptibility to fire damage, and the like.